Volcano enthusiasts have enlisted the help of a University of Manchester academic to come up with a list of the top ten most dangerous volcanoes in the world. And the Japanese island of Iwo Jima, which was invaded by the US army during the Second World War, has been identified in the number one spot. The list includes volcanoes which have a realistic chance of erupting in the next 100 years and which risk causing the deaths of 1,000,000 people or more.